Shelf



FIG. 1 is a front perspective view of a shelf;

FIG. 2 is a top plan view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a back elevated view thereof; and,

FIG. 6 is a right side elevational view thereof with a left sideelevational view being a mirror image thereof.

The broken lines are for the purposes of illustrating the environment ofthe article only and form no part of the claimed design.

CLAIM The ornamental design for a shelf, as shown and described.